Greenfield
Adventurer
The Save ve Disguise Self is in no wy related to the Save v Dust of Illusion. One is to see through it, the other is to resist having the effect go off at all. Additionally, Dust of Choking and Sneezing allows a Save, and has already been mentioned in this discussion.Two dusts list saving throws: Dust of dryness (which is not based on a spell) and dust of illusion (which is based on disguise self and lists the saving throw as an exception to the way the disguise self spell normally works).
Maybe circular logic flies where you live, but around here it kinda falls flat. Dust of Disappearance doesn't list a Save. Presuming that it does, and then using that to support the claim that it does, or to tear down arguments that it might not is really bad logic, and really poor argumentative technique. Since I'm forbidden from saying what I think of your mental processes, I'll simply ask that you stop presuming that we're all fools.There is, in fact, only one dust which is based on a spell which allows a saving throw -- which would be the dust of disappearance we're talking about. So looking to the other dusts for precedence of how this issue is handled in D&D isn't particularly valuable.
And you would be wrong because there's a strong precedent set for "Greater" versions of spells to be based on the lesser. In fact, there's a section in the rules describing this very thing.And they would be wrong. The only way such a ruling would make sense is if they similarly allow wizards to cast greater invisibility without taking an action because the spell doesn't list a casting time. This is simply not the way the rules work. And if you think it is the way the rules work, adjudicating the use of dust of disappearance is going to be the least of your problems.
Magic items, on the other hand, frequently operate in ways completely different from the spells used to create them. And by "frequently" I mean "almost always".
Examples: SR doesn't apply against Flaming weapon, even though the item has a caster level and a base spell needed to create. Bracers of Armor are based on Mage Armor, but can give bonuses other than +4. A Necklace of Missiles can include Fireball missiles below 5 hit dice, even though 5 is the minimum caster level to throw Fireball at all. One of the Quall's Feather Tokens can create an oak tree, as an instantaneous effect (hence no duration) even though the item is based on Major Creation. The tree far exceeds the volume limit for the spell (five foot diameter trunk, sixty feet high, forty foot diameter crown), and the spell never lets you create living things.
I could go on, but if you want a more complete list just look in the DMG. Other than items which explicitly cast spells, such as wands, scrolls, etc., almost none of the items operate the way the spells used to create them do.
So, in conclusion, you have basic facts wrong, your logic is circular, and your examples are weak at best.